Heat exchange apparatus



Aug. 1, 1939. A. J. LARRECQ HEAT EXCHANGE APPARATUS Filed Jan. 22, 1958 Inventor-2 l Anthony J.- LaTTeCq,

Patented Aug. 1, 1939 UNITED STATES lPATENT OFFICE HEAT EXCHANGE APPARATUS New York Application January 22, 1938, Serial No. 186,348

1 Claim.

This invention relates to heat exchange apparatus for vehicles. Although not limited thereto, the invention is particularly adaptable for condensing the exhaust of elastic fluid engines embodied in an aeroplane structure so that the operating fluid may be continuously re-utilized.

It is desirable that aeroplanes propelled by elastic fluid engines or turbines be provided with heat exchange apparatus for condensing the exhaust from the turbines to prevent the loss of operating fluid and thus reduce the supply of necessary make-up fluid to a minimum.

It is an object of this invention to provide heat exchange apparatus in the aeroplane wing structure in such manner as to cause minimum resistance to the flow of cooling air.

It is a further object of this invention to provide .heat exchange apparatus as an integral part of the wing structure, preferably along the leading edge thereof in such manner as to offer no additional aerodynamic drag.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 shows a plan view of an aeroplane structure embodying my invention; Fig. 2 is a perspective view, partly in section, through one of the wings showing various details of the condenser arrangement; Fig. 3 is a cross-sectional view of one of the condenser units and Fig. 4 is a detailed view, partly in section, of another of the condenser units.

Referring to the drawing, an aeroplane I is shown having a fuselage II and wings I2 and 3 extending on either side thereof. The elastic fluid engines or turbines |4 for driving the propellers I5 are shown in this instance as being mounted on the ferward edge of the wings on either side of the fuselage, it being understood, of course, that the engines may be mounted otherwise on the aeroplane structure and that the arrangement shown is merely exemplary. Elastic uid engines I4 are coupled to the propellers through suitable reduction gearing yarranged in a housing I6 provided between the engine and the propeller. Elastic fluid for operating the engines may be generated in suitable boilers I1 arranged in the fuselage which are connected with the engines by conduits I8 having suitable flow controlling valves I9 disposed therein. The exhaust from the elastic fluid engines is led through conduits 20 into the heat exchange apparatus of my invention comprising two condensing units 2| and 22 for each engine, which units are embodied in the wing structure as will be described with greater particularity hereinafter. The condensate is drained from the condensers by conduits 23 and is forced by suitable boiler feedl pumps 24 through conduits 25 back into the boilers I1.

The condenser 2| comprises a plurality of units 26 arranged side by side and in parallel connection, each having upper and lower headers 21 and 28 respectively. A plurality of heat exchanging condenser tubes 29 communicate with the headers, the tubes being provided with ns 30 for increasing the radiating surface thereof. The

y exhaust from one of the engines I4 is fed into the upper header through a branch of the exhaust conduit 20, the fluid passing through the tubes 29 in which condensation takes place. The condensate flowing from thev lower ends of the tubes into the lower header is drained therefrom by the conduit 23 to the pumps 24. The air and other non-condensables entrained with the elastic fluid are passed through a group of aftercooler tubes 3| arranged on the lower side of the condenser unit in such a manner that cooling air contacts these after-cooler tubes before such air reaches the condenser tubes. Any trace of steam entering into the after-cooler section will be condensed therein draining back into the lower header 28. The non-condensables will pass into the header 32 joining the upper ends of these tubes adjacent the header 21 from which header the non-condensables are drawn by any suitable means (not shown) connected to the conduit 33 and exhausted to atmosphere. The units forming the condenser 2| are secured in position in the central section of the wing structure between the upper and lower webs 34 and 35 thereof and immediately adjacent the engine I4 necessitating only short exhaust conduit connections therebetween. Preferably, the condenser units are supported in any suitable manner between the fore and aft wing spars 36 and 31 respectively at an angle with respect to the normal horizontal position of the wing with the inlet header higher than the.out1et header so that 'the condenser tubes therebetween slope in such a manner that the condensate will flow from the tubes during any normal position of the wing. By the angular arrangement of the condenser, the tubes thereof may be of sufficient length to enable proper condensation of th elastic fluid to take place therein.

Cooling air for the condensers is admitted,

through a slot opening 38 provided along the forward edge of the wing at the underside thereof. The air scooped into this opening at a rather high velocity is conducted through a passage 39 defined4 by the lower web 35 vand a wall 4U and is diffused in the diverging end of the passage 39 by blades 4| which direct the air flow past the finned tubing of the condenser units. The air after passing the condenser is discharged through an opening 42 provided in the upper surface of the, wing and toward the rearward edge thereof. Louver blades 43 extend across the opening 42 and are So shaped as to direct the air flow therethrough in the relative direction of the air flow over the outer surface of the wing.

It is further desirable to provide an additional condenser unit extending along the leading edge of the aeroplane wing as indicated at 22 in the drawing. This unit may be provided with a smooth outer surface conforming in contour to that of the wing surface and is so arranged that considerable additional condenser capacity is obtained with little additional weight, and no additional aero-dynamical drag. As indicated, the condenser 22 comprises a smooth outer shell 44 curved to conform in contour with the leading edge of the wing and similarly curved inner shell 45 which is provided with a plurality of corrugations 46 extending transversely with respect to the wing and terminating in a longitudinal yupper header .41 and a longitudinal lower header 48. The parts 44 and 45 may be pressed from single sheets of suitable metal such as stainless steel, copper or aluminum and may be line welded together to form a sealed chamber therebetween. The corrugations 46 in the lower shell cooperate with the inner smooth surface of the upper shell 44 to form a plurality of tubular passages for elastic fluid between the upper and lower headers.

lIhe condenser is so arranged that upper headeij` the condenser 22 is connected with the exhaust conduit 20 extending from the elastic fluid engine while the condensate passes together with the non-condensables through the conduit 49 into the lower header 28 of the condenser unit 26. It is understood, of course, that the header 28 is substantially lower than the header 48, to insureproper drainage of the latter. The noncondensables are drawn from the header 28 through the after-cooler tubes 3| of the condenser unit 2|` in which separation of the non-condensables from the vapors takes place and are exhausted to atmosphere from the header 32.

An added advantage procured through the arrangement of a condenser section along the leading edge of the wing lies in the fact that the formation of ice along this edge is minimized. It is a well-known fact that ice formation tends to localize along the leading edges of the Wings of the aeroplane and the provision of a heated surface at this point minimizes this difficulty.

While I have described the condensing apparatus as comprising two distinct units arranged in parallel connection, it is understood that the provision of a second unit 22 is not essential to the practice of my invention. The additional unit is preferred, however, since the total condenser capacity is considerably enlarged thereby at the expense of little additional weight. A maximum of condensing capacity is required particularly at starting or at take-off when the exhaust from the engine is much greater than when the aeroplane is cruisingat a normal speed. It may be inadvisable to attempt to provide sufficient condensing capacity to maintain a desirable low condenser pressure during the abnormal starting condition particularly when the temperature of cooling air is high. During such conditions it is preferred to discharge part of the exhaust from the engine to atmosphere to maintain the condenser pressure within permissible limits. I have shown a relief valve 50 provided in the exhaust conduit or header feeder 20 which may be opened during the starting period to release a portion of the exhaust uid therefrom. This valve may be either manually or automatically controlled as desired, it being understood, of course, that it is to be adjusted to the closed position as soon as the aeroplane attains the normal cruising condition of operation.

While I have shown this heat exchanger apparatus as adapted for condensing the exhaust of elastic fluid propelling engines, it is understood that this invention is not necessarily limited to the modification shown. The heat exchanger apparatus shown may be equally effective in cooling evaporative fluid utilized for cooling internal combustion engines of aeroplanes. When used for the latter purpose, the unit 22 may of itself be suflicient for suitably cooling the circulating fluid, thereby combining the advantages of an efficient heat exchanger andmeans minimizing the formation of ice on the wings.

It is further understood that the heat exchange apparatus herein described as adapted for aeroplanes is not necessarily limited for use in connection with vehicles of this type only but may be used equally Well with land vehicles. Thus, the condenser unit 2| may be arranged within ,n any body portion of such vehicles having an aii` passage extending therethrough for conducting cooling air past the condenser tubing. The units 22 may be provided on any convenient surface or wall of such vehicle exposed to a flow of cooling air moving relatively therepast.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have vit understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to obtain by Letters Patent of the United States is:

In combination, an aeroplane, an elastic fluid turbine for propelling said aeroplane, heat exchange apparatus for condensing the exhaust therefrom, said apparatus comprising a pair'of condenser units, the first condenser unit of said pair being disposed along a portion of the leading edge of said wing and having an outer wall constituting a part of the wing surface and conforming with the contour of the remainder of the wing surface and an inner wall secured thereto, upper and lower headers in said first condenser unit, a plurality of fluid passages defined by said Walls communicating between said headers, the second condenser unit of said pair disposed within the central portion of said wing between the upper and lower surfaces thereof and comprising an upper and a lower-header having a plurality of extended-surface condenser tubes therebetween, an after-cooler including a plurality of extended-surface tubes communicating with said lower header of said second unit for receiving non-condensables therefrom, a conduit for conducting condensate and non-condensables from the lower header of said rst unit to the lower header of said second unit, a conduit for conducting condensate from said lower header of said second unit, a conduit for conducting noncondensables from said after-cooler and a passage through said wing for conducting cooling air into contact with the condenser tubes of said second unit.

ANTHONY J. LARRECQ. 

